NEW YORK -- Winning the biggest game of college football's opening weekend boosted LSU to No. 2 in The Associated Press Top 25.

No. 1 Oklahoma held on to the top spot in the first regular-season rankings, while the Tigers used their 40-27 victory against Oregon to jump rival Alabama, which slipped to No. 3.

"It's way too early to feel like we have accomplished anything," LSU coach Les Miles said. "Our guys understand the need to improve each game."

The Sooners received 32 of 60 first-place votes and 1,448 points. LSU received 17 first-place votes and 1,415 points.

Alabama had nine first-place votes, and two voters had No. 4 Boise State top-ranked after the Broncos' impressive 35-21 win against Georgia. Florida State moved up to No. 5.

Oregon dropped nine spots to No. 13 and defending national champion Auburn, which started the season at No. 23, fell out of the Top 25 after needing a late rally to beat Utah State 42-38 at home.

The Tigers became just the second defending national champions since the preseason poll started in 1950 to fall out of the rankings after the first week of the season in the first regular-season poll -- though the circumstances were far different the first time it happened.

Alabama, the 1964 AP champion, started the '65 season ranked No. 5. The Crimson Tide lost 18-17 to Georgia to open the season and dropped out, but The Associated Press only ranked 10 teams that season. Alabama eventually returned to the Top 10 and won another national title.

The 1961 Minnesota team is the only defending champion to be unranked in the preseason poll.

Moving into this week's rankings were No. 20 Baylor, which beat TCU 50-48, and No. 22 South Florida, 23-20 winners at Notre Dame.

"When you look at it, the one that I'm most concerned about is the last one," Bulls coach Skip Holtz said. "After the end of the year we'll talk about the rankings and all that because that's the only time it really matters. So what we've got to do right now is just focus on what we've got to do on a day-to-day basis."

Also ranked for the first time this season were No. 23 Penn State and No. 24 Texas. The Longhorns started the season unranked for the first time since 1998.

Penn State moves into the rankings ahead of Saturday's home game against third-ranked Alabama. It's the only game this week matching ranked teams.

TCU dropped 11 spots to No. 25.

Notre Dame and Georgia tumbled out of the Top 25 after losses. Like Auburn, Southern California, which opened the season ranked 25th, fell out of the rankings after a victory. USC squeaked by Minnesota 19-17.

The rest of the top 10 had No. 6 Stanford, followed by Texas A&M, Wisconsin, Oklahoma State and Nebraska.

No. 11 is Virginia Tech, followed by South Carolina, Oregon, Arkansas and Ohio State.

The Big Ten has five ranked teams, with No. 17 Michigan State joining Wisconsin, Nebraska, Penn State and Ohio State.

No. 19 West Virginia and USF give the Big East two teams in the Top 25. The Atlantic Coast Conference (Florida State and Virginia Tech), the Pac-12 (Stanford and Oregon) and the Mountain West (Boise State and TCU) also have two ranked teams.